Receive:

  • Filtrate of varying osmolality

Process:

  • Minimal Na+ and K+ reabsorption
  • H2O reabsorption.

Produce:

  • Aldosterone: steroid hormone that acts to increase Na+ reabsorption. At the same time it enhances K+ and H+ secretion.
  • Vasopressin (ADH):
    • Brings aquaporins to the apical surface
    • Makes collecting ducts permeable to water, otherwise water reabsorption is very low

Export:

  • Urine of varying osmolality